This invention relates generally to mechanical resonators, and more particularly the invention relates to a microresonator structure and method of fabricating the structure.
A mechanical resonating structure or resonator functions as a stable or tunable frequency source which can be used as a timing device, a filter, or as a carrier frequency in communications. Mechanical filters primarily comprise macroscopic quartz and ceramic resonators, while a microelectromechanical system (MEMS) resonator utilizes a clamped-clamped or free-free beam, see Nguyen “Vibrating RF MEMS for Low-Power Wireless Communications,” Proc., 2000 International MEMS Workshop, Singapore, Jul. 4-6, 2001, pp. 21-34, for example. The Nguyen free-free resonator, for instance, is a cantilever structure utilizing a polycrystalline silicon (poly-silicon) free-free beam fabricated using semiconductor processing techniques. The Nguyen free-free structure utilizes four support beams attached at the quarter wavelength nodes of the flexural beam. The four support beams are anchored to the substrate.
The present invention is directed to a MEMS resonator having three-dimensional resonance vibration with a high mechanical quality (Q) factor and which is readily fabricated using conventional semiconductor manufacturing processes.